How much daa do you have and what is the timeline? If you can manage with a maintenance window the snapshot / move and restore method may be the fastest. Streaming data can take
a long time to sync two DCs if there is a lot of data.

we need to move our existing cassandra cluster to new hardware nodes. Currently the cluster size is 8 members, they need
to be moved to 8 new machines. Cassandra version in use is 3.11.1. Unfortunately we use materialized views in production. I know that they have been marked retroactively as experimental.

What is a good way to move to the new machines? One-by-One, or setup a new cluster as a separate DC? The move should be
done without downtime of the application.